1. Field
The present disclosure relates generally to the aircraft and in particular, to a method and apparatus for operating an aircraft. Still more particularly, the present disclosure relates to a method and apparatus for dynamic roll angle stall protection.
2. Background
During operation, an aircraft may fly in the air as a result of an aerodynamic force called lift. Lift is generated by the wings of an aircraft as air flows past the wings as a result of forward movement of the aircraft. The wings of an aircraft generate lift because of a pressure reduction on the upper side of the wings. The lower pressure on the upper side of the wing combined with a higher pressure on the underside of the wing provides the lift. Lift may be increased by increasing the angle between the wing chord and the relative airflow. This angle is also referred to as an angle of attack.
With the increase in the angle of attack, drag also may increase. Without sufficient engine power, the aircraft may slow, further decreasing the wing lift. When the angle of attack increases above a selected angle, the airflow becomes turbulent, and the lift may disappear causing the aircraft to “stall” because the wings cease to provide sufficient lift to support the aircraft. This angle is also referred to as a critical angle of attack.
This type of stall may occur in a number of different situations. For example, a stall may occur during a climb and/or a bank maneuver. A climb or descent maneuver typically is used to change the altitude of the aircraft. The change in altitude is also referred to as vertical maneuvering. The maximum lift capability of the aircraft may be exceeded when a steep bank occurs while descending and capturing altitude during low-speed maneuvers, which may result in stalling the aircraft. A stall also may occur if a climb is initiated from a situation in which the aircraft is in a steep bank while the speed is slow and the climb is initiated.
Therefore, it would be advantageous to have a method and apparatus to overcome the problems described above.